Microstructural evolution occurs in solid oxide fuel cells (SOFCs) during operation, which cause severe electrochemical performance degradation as well as structural failure such as crack formation. Nickel (Ni) particle coarsening is believed to cause microstructural evolution in the Ni-based anode of SOFCs. Furthermore, the accumulation of expanded pores during the microstructural evolution is responsible for crack formation. Based on the diffuse-interface theory and the phase-field method, integrating both Cahn-Hilliard equation and Ginzburg-Landau equation, a meso-scale phase-field model was established to investigate microstructural evolution and crack formation in the Ni / Yttria Stabilized Zirconia (YSZ) anode of SOFCs. Then, the model was applied to explore the coupling effects of microstructural evolution on SOFCs performance degradation. Simulation results show that particle size, porosity, and particle size ratio of Ni-YSZ are most influential parameters in microstructural evolution. It was found that the triple phase boundaries (TPBs) area was decreased by 24% and power density was decreased by 11.03% after 1000 hours of operation. In addition, the power density was decreased by 27%. This work is expected to provide us a comprehensive understanding of SOFCs' microstructural evolution as well as a tool for SOFC's performance degradation analysis. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.